zoj1221_Risk（多源点最短路）

#include<iostream>
#include<vector>
#include<cstdio>
using namespace std;

int map[25][25];

void floyd()
{
for (int k = 1; k <= 20; k++)
for (int i = 1; i <= 20; i++)
for (int j = 1; j <= 20; j++)
{
if (map[i][j] > map[i][k] + map[k][j])
map[i][j] = map[i][k] + map[k][j];
}
}

int main()
{
int t = 1;
int n;
while (~scanf("%d",&n))
{
for (int i = 1; i <= 20; i++)
for (int j = 1; j <= 20; j++)
map[i][j] = 999999;
for (int i = 0; i < n; i++)
{
int a;
scanf("%d", &a);
map[1][a] = 1;
map[a][1] = 1;
}
for (int i = 2; i < 20; i++)
{
int sum;
scanf("%d", &sum);
for (int j = 0; j < sum; j++)
{
int a;
scanf("%d", &a);
map[i][a] = 1;
map[a][i] = 1;
}
}
floyd();
printf("Test Set #%d\n", t++);
int m;
scanf("%d", &m);
for (int i = 0; i < m; i++)
{
int a, b;
scanf("%d %d", &a, &b);
printf("%d to %d: %d\n", a, b, map[a][b]);
}
printf("\n");
}
return 0;
}